Collaborative Research: Comparative Breeding Structure of Four Species of Sonoran Desert Columnar Cacti

9421673弗莱明索诺兰沙漠是世界上最茂盛、物种最丰富的沙漠。在其独特的适应干旱的植物中，突出的是四种柱状仙人掌：Saguaro(Carnegia Gigantea)、风琴管(Stenotherus Thurberi)、senita(Lophocereus Schttii)和Cardon(Pachyereus Pringlei)。这些物种通常以高密度出现，代表了其群落中大部分活的植物生物量，并作为食物(花蜜、花粉、水果和种子)的来源和大量沙漠动物的庇护所。尽管有明显的生态环境，但它们的生殖生物学以及不同种类的传粉者对它们繁殖成功的重要性。在这项研究中，我们将进行实验，记录蝙蝠、飞蛾、鸟类和蜜蜂对柱状仙人掌授粉成功的相对贡献，并分析这些传粉者产生的果实中种子的遗传组成。我们的总体目标是了解不同类型的传粉者是如何影响其食用植物种群的遗传结构的。对沙漠植物繁育系统的研究特别重要，因为它们极具间歇性的招募(仙人掌种群平均每十年才有一年获得新个体)可以对其种群中个体的遗传构成产生长期影响。因此，对四种柱状仙人掌的研究将成为传粉生物学研究的模式系统，并为形成沙漠植物物种遗传多样性的过程提供新的见解。我们的研究将是迄今为止最详细的关于不同类型的传粉者对开花植物繁育系统的贡献的图景。如果我们要了解传粉者在植物物种形成中的作用，植物与传粉者相互作用的起源，以及人类干扰导致传粉者丧失对植物的潜在遗传后果，这些知识是至关重要的。

9421673 FLEMING The Sonoran Desert is the lushest, most species-rich desert in the world. Conspicuous among its uniquely drought-adapted plants are four species of columnar cacti: saguaro (Carnegia gigantea), organ pipe (Stenothereus thurberi), senita (Lophocereus schottii), and cardon (Pachycereus pringlei). These species often occur in high densities, represent much of the living plant biomass in their communities, and serve as sources of food (nectar, pollen, fruit, and seeds) and shelter for a large number of desert animals. Despite the obvious ecological their reproductive biology and the importance of different kinds of pollinators for their reproductive success. In this study, we will conduct experiments to document the relative contribution of bats, moths, birds, and bees to the pollination success of columnar cacti and will analyze the genetic composition of seeds in the fruits produced by these pollinators. Our overall goal is to understand how different kinds of pollinators affect the genetic structure of populations of their food plants. Studies of the breeding system of desert plants are of particular importance because their extremely episodic recruitment (cactus populations gain new individuals in only one year in ten, on average) can have long-lasting effects on the genetic composition of individuals in their populations. Thus, the examination of four species of columnar cacti whose flowers are visited by different combinations of bats, birds, and insects will serve as a model system for studies of pollination biology as well as provide new insights into the processes that shape the genetic diversity of desert plant species. Our study will be the most detailed picture of the contributions of different kinds of pollinators to the breeding systems of flowering plants to date. Such knowledge is critical if we are to understand the role of pollinators in plant speciation, the origin of plant-pollinator interactions, and the potential genetic consequences to plants o f the loss of pollinators through human disturbance.